Posted
by
kdawsonon Tuesday November 17, 2009 @03:14PM
from the lamp-unto-your-feet dept.

MikeChino writes "Sifting through minefields to remove hidden threats is a dangerous, tedious, and expensive process. Scientists at the University of Edinburgh recently announced that they have engineered a strain of bacteria that glows green in the presence of explosives, making mine detection a snap. The new strain of bacteria can be sprayed onto local affected areas or air-dropped over entire fields of mines. Within a few hours the bacteria strain begins to glow wherever traces of explosive chemicals are present."

I had a co-worker from Afghanistan in the past (nice guy). He said that his uncle would do it is to buy a field with land mines on it for cheap and then just let a herd of goats graze the property. If a goat exploded, that one was dinner.

That might happen under natural selection, after a few hundred (thousand?) years. But we artificially select these bacteria for their ability to glow in the presence of boom-dust, therefore natural selection is irrelevant.

As long as it doesn't result in any false negatives, I think it sounds like a great product for speeding up sweeping. Even if half of a 'field does end up alight, at least they can ignore the dark portions and concentrate on the lit areas.

In a sparsely mined area it could save weeks, months or years of painstaking work - or a few limbs in the case where currently nobody is bothering to sweep the area clean at all.

The next step is for the bacteria to auto dissolve the explosives, kind of like that blue stuff

Well, it depends on how sensitive the bacteria are. Over time, rain, sun, organic processes, etc., will probably wash away and break down the explosive residue you spread, whereas it would continue to evaporate/disseminate from the actual mine locations. That would mean that long term mine fields like those on the North Korea DMZ would effectively be vulnerable unless you were prepared to re-seed the fields regularly with explosive residue (an expensive proposition). In the end, this might remove the last h

In most soils, there live denitrifying bacteria, whose metabolism is based on reducing oxidized forms of nitrogen, eventually turning it back into nitrogen gas which reenters the atmosphere. These bacteria are recyclers, generally getting on by "unfixing" the fixed forms of nitrogen most other organisms rely on to survive, and so tend not to be picky about their nitrogen sources. They have enzymes called flavoprotein reductases that let them get nitrogen from organic nitrates, like from decaying organic matter. It turns out, however, that these enzymes also let them use many of our most common nitrated chemical explosives as a nitrogen source as well. In fact, one such enzyme has even been named PETN reductase, like the PETN that's in Semtex. I'm saying that if you spray liquid explosive on soil, the bacteria that already live there will eat it like candy. The mines would far outlast the spraying, which is exactly the problem- landmines around the world have far outlasted the conflicts they were laid for in the first place.

The method proposed by this group from Edinburgh actually takes advantage of that process, though. An old landmine or unexploded ordnance is probably going to be slowly leaching explosive out of the weapon. This means that soil near the device will contain the explosive itself, and also nitrites, which are produced as an intermediate step of breaking down the explosive material.

The group set up a sort of two-factor authorization. They genetically engineered promoters, proteins that bind to DNA and promote transcription of a particular genetic sequence, for two fluorescent proteins. Nitrite ion binds to the promoter for luxAB.GFP, which is a fusion protein of bacterial luciferase and green fluorescent protein. Thus, whenever nitrites are present, this protein gets made, and the bacterium glows a pleasing blue-green color. Not just fluoresces, mind you, but actively puts out light, due to the luciferase part. There is another sequence, for enhanced yellow fluorescent protein (eyfp). That promoter is activated by the presence of trinitrotoluene; the group used computational methods to develop a protein that binds DNA if it is also bound to TNT. Unlike the luxAB.GFP fusion protein, eyfp only fluoresces. It will glow yellow only if higher energy light has been input. So if pure TNT were present, the bacterium would make eyfp, but would only glow under UV light. When only nitrites are present, it actively glows blue. When both are present, the luxAB.GFP dumps light on eyfp, and the bacteria actively glow yellow. And then you call the bomb squad.

Hey now, I was simply pointing out an obvious shortcoming to the potential usefulness of this in an area where insurgents still want to keep it mined. When used to clean up abandoned minefields, I think this product has the potential to save tons of lives (and limbs). No need for you to wish me into the middle of a minefield simply because I pointed out a potential countermeasure to the product.

It looks like the University of Edinburgh entered this project in the International Genetically Engineered Machine competition, so they have a project page [igem.org] with a lot of information. From what I gather, it would appear that the system is based on a system of enzymes that break down soil nitrites which have been linked to Green Fluorescent Protein. Nitrites are a natural byproduct of the breakdown of nitro-based explosives like TNT and PETN. Of course, soil nitrites from non-leaking landmine sources, like chemical fertilizers would also trigger fluorescence, so the team engineered a non-natural gene promoter protein. The genes to produce the fluorescent complex only get transcribed and translated into protein if the promoter is active. The activator for that promoter is a molecule of TNT, so the bacteria will only glow if TNT is present.

I'd also encourage people to take a look at the other iGEM projects [igem.org]. Lots of interesting reading.

In the old days, if you wanted to do the area denial thing, you had to buy these expensive, heavy, hard to install landmines.

Then it was discovered you could scare the other guys away merely by using signs that say "landmine". In fact there is a UN standard / requirement for posting landmine signs around a minefield, scary white triangles, if I recall...

Now, technology marches on, and all you need is a big pack of green chemlights from walmart... crack them, drip the liquid in a field, and instant, cheap, area denial... Its also economic warfare, since mine field clearing is very expensive compared to buying a bunch of chemlights. Its also very demoralizing to the troops to know that glowing stuff might or might not be fake.

Now they'll either lace the entire field with C4, or they'll start using remote detonators when people move in to disarm.

The largest problem with land mines is that there are so many in areas where there is no longer any kind of combat - kids or other civilians go in the fields and lose life and limb. This helps with that. We're talking WW2 era stuff here.

Modern warfare by insurgents is ALREADY past mines, since they don't have an endless amount of money to spend - they already place explosives and use remote detonators when troops come by.

I wouldn't say that they're "past" mines, if anything they lack the resources and facilities to make a proper mine, instead what they make are called Improvised Explosive Devices (IED's) which can perform the job of a mine, but can't withstand the elements for decades like a properly encased munition mine can. Sure, many are triggered manually, but a pressure plate trigger can be made from the ringer out of a typical telephone - a piezo transducer, same thing used to measure earthquakes. Wire that through a relay to a diesel-nitrogen cocktail, and it'll take the treads off a tank no problem, but it couldn't last more than maybe 5 years before the batteries die.

Take a look at the tanks and APV junkyards in Afghanistan and try telling the repair crews there aren't any mines out there. And there are definitely booby traps in buildings where the bacteria could come in handy for sure.

Modern warfare by insurgents is ALREADY past mines, since they don't have an endless amount of money to spend - they already place explosives and use remote detonators when troops come by.

What you've said is not true. I said this to someone else, and at the risk of being modded redundant- BOTH triggers are used in Afghanistan against US troops. Remote detonation falls to the age-old electronic counter measure and it's best defense is a higher power jamer. This is compounded by the fact that the cheapest way to remote detonate is with cellphones, which only operate over a limited & known range of frequencies. Because of this flaw other types of triggers (force/pressure based) are still used (and because for pressure based explosions no enemy has to be physically present ['set it and forget it']).(I work in land mine detection)

The biggest danger with mines is not that they explode - it's that no one really knows where the mines are, and that they are often right around civilian areas.

Your two scenarios would actually both be a vast improvement over the current situation.

In the first instance, you just have to get one little corner to detonate, and the entire field should go off. At that point, de-mining via artillery-shelling will actually work. If you meant to say that the mine fields are going to be much denser, great as well - you can actually employ large-scale de-mining equipment and have it be more cost-efficient than the hand-demining.

In the second instance, people sitting at a remote trigger actually make the mine safer: it means that there are less mines to go around (detonators are scarce, mines are not), someone knows where the mine is and it won't randomly go off when a kid decides to play catch in the field.

A properly laid mine field will not suffer from sympathetic detonation of another mine. Most mines are placed 5 meters apart or more. Artillery is effective against certain types of mines, ones with trip wires or tilt rods, even then I would hesitate going in unless under a more serious threat (ie direct fire).

A single mine with a remote detonator is barely effective. The whole point of a mine is place it, and forget it. If you need someone (or 2) to babysit it cuts into you combat effectiveness.

In the first instance, you just have to get one little corner to detonate, and the entire field should go off.

Any other genius thoughts you'd like to share with us? Like how it's easy to sink a battleship, all you have to do is make a hole the right size in the right place.

Seriously, do you think military engineers haven't worked out how to set mines so that 300 mines cause more than one casualty? If one man set off an entire minefield it would hardly be worth getting your spade dirty planting them, would it? You'd do more harm to the enemy throwing the bastard things at them.

You're not an armchair general. You aren't even a moron. You're an armchair moron.

Now they'll either lace the entire field with C4, or they'll start using remote detonators when people move in to disarm.

The real problem is there is no magic biological way to detect explosives, like the force, or some DnD "reveal invisible" spell.

So, what'll happen, is anywhere the mines have degraded and cracked open and are thus probably inert, will glow green, so people will avoid those "dangerous" areas, and anywhere the mines remain hermetically sealed, will not glow, thus it looks "safe" but is actually very dangerous.

Even worse, its not failsafe. If a spot is not glowing, is that because coverage was not 100% becaus

So, what'll happen, is anywhere the mines have degraded and cracked open and are thus probably inert, will glow green, so people will avoid those "dangerous" areas, and anywhere the mines remain hermetically sealed, will not glow, thus it looks "safe" but is actually very dangerous.

If machine scanners can detect explosives what makes you think living things can't? Are these scanners just scams to get money from airports, border crossings, and seaports?

This could be a setback, but my guess is that there would be a "glowing bacterial density" that you could look at. If everything's faintly glowing green in an area, then there's a spot where it's bright green, you'd take special care around that spot.

So can I add this the list of possible humanity-ending catalysts and/or future Michael Crichton novel plotlines?

The one I'm waiting for is a genetically-engineered cellulose-to-ethanol bacterium that can survive in the wild. With all of the biofuel companies rushing to come up with a commercially-viable product, there's lots of opportunity for an accident to unleash a critter capable of eating all plant life on earth. It will doom humanity, but at least we'll have lots of cheap booze to drink as the planet withers and dies.

Am I the only one here who is aware of how bad of a problem land mines are to civilians in many third world countries? The response here seems generally negative, but if this technology helps to diffuse old land mine fields, it would be wonderful. Just because it was planted in WW2 doesn't guarantee that it's become inactive or that it won't kill you now.

The problem is, all these critics are a teeny bit right when they say it's not going to work. Alas.

Not so very many years ago, there was an initiative to grow flowers whose petals turn red if they hit a mine. A lot more practical than bacteria, and it seemed to work very well, too -- but they got booted out of that African country they were testing in rather rough-handedly. It's a sad tale, but the fact is there are more warmongers than do-gooders and these things are immensely difficult to see to fruition.

Well noted - it's a lot of the old mines that people have forgotten about that continue to cause problems. I've visited Cambodia and there are a lot there because of the Khmer Rouger period there, and in Laos and Vietnam there are a lot due to the "Vietnam War" as we think of it in the West from over 40 years ago. Lots of other conflicts in Africa and other places as well. Not so bad if you're in a rich country or you've got resources that people want access to (e.g. oil) but a lot of places have just been

Seems like this could massively reduce the military usefulness of minefields. Isn't a huge minefield sitting on the border between North and South Korea helping keep the peace there, by deterring North Korean military aggression? What if the North Koreans can spot all the mines?

It's not like it was impossible to detect and disarm mines before this. It was just more time consuming and expensive. Mines are just one aspect of the Demilitarized Zone, and would be basically useless by themselves. There are troops from both countries patrolling their side of it in case anyone tries to cross over, and massive amounts of guns and artillery. Nevertheless, the North has gone on incursions in to the South's side of the DMZ. And the biggest threat from NK has been the tunnels they dug al

Not really. The DMZ (as far as I know) is the only place where a minefield still actually serves a military purpose. Furthermore, without an ability to disarm the mines remotely, it wouldn't be that advantageous to know where they are, since the North Korean forces would be maneuvering to avoid the mines and would be much more vulnerable to counterattack. The US and the South would know they were coming from troop buildups and the spraying of the field with bacteria (it takes a few hours to activate). A

There's nowhere on earth usefully defended by minefields alone. Not even the DMZ. And if you could sit and spray the mine fields with this bacteria and disarm/maneuver between them unmolested, then you could have done that yesterday. But they don't (outside of small incursions), because there's a hell of a lot more firepower than just mines that is being pointed across the DMZ.

Exactly. They have the logic backwards. What if an area didn't get covered in spraying? So that area would be "dark" and they think it's safe? Yikes, that's a false negative. They need to reverse it to avoid that false negative.

If the bacteria only glow WITHOUT the presence of landmine. That way, at best you get false positives which is less dangerous than a false negative, in this situation.

Why do I get the feeling, when slashdoters discuss military tactics and strategies, that we're inside some kind of "Enders Game" scenario, and some pentagon general, recently reassigned from SG-1, is high-fiving cmdr taco right now, over our great insights into warfare?

A friend worked overseas in ordnance disposal. It is, by most accounts, one of the most dangerous job out there. He left, but I'll be quite content if I know more soldiers and peacekeepers in the future will be kept safer.

Even if this thing had a 100% success rate, I'd still be cautious about clearing the minefield. But this can at least help where you know with some certainty there are mines in the area, and you will have some certainty there is a mine in that location or within the vicinity.

I assume they probably engineered the bacteria so it doesn't survive indefinitely, but it would be interesting if it mutated and began spreading and eventually spread to every corner of the world, so any place that had explosives would glow!

Without RTFA:1 - Rocks and nearby puppies.2 - Bacteria are asexual. These bacteria will, however, be able to spread an "asexual agenda" among native bacteria, who will begin to glow in the presence of other objects, like discarded cans, to look cool and "green."3- Except for puppies, the bacteria are harmless. Unless you like eating gunpowder or landmines.4- More landmines! No, wait, they'll be outbred by normal bacteria soon enough.

Bacteria do, however, exchange DNA with nearby organisms, not necessarily of the same species. Some DNA has been incorporated into "infected" hosts, or picked up through plant root systems, and bacteria shuffle DNA between themselves, as well.

There's more to knowledge than just mis-quoting some Wikipedia article, since the one you referenced does, in fact, describe gene transfer (BTW, use the URL tags).

> What assurances do we have that the bacteria won't mutate, self-replicate, or> turn against its master in the form of some horrendous new super-bug that> makes the 20,000 land-mine casualties a year seem like a drop in a bucket?

None. And the sames goes for the millions of other species of bacteria that infest every square meter of the Earth's surface.

Note quite right. The assurance IS the millions of other species of bacteria. All life is compromise, and a bacteria which mutates and becomes ultra-lethal to humans will probably be eaten by its neighbour bacteria, which is more suited for such mundane things as surviving in the soil where they live.

It's the same reason why the grey-goo scenario is silly. The earth may look beautiful and pristine, but in reality it's a shockingly hostile environment. You've got a corrosive atmosphere (full of nasty oxyge

You do realize that bacteria are everywhere right? Just because we modified this one to glow doesn't give it some unique survival advantage or propensity to mutate. If anything, the bacteria is going to be a monoculture and more susceptible to chemicals and preditors.

Anyone else get a slightly uneasy feeling at the idea of crop-dusting entire areas of land with living bacteria that glow?

Did you ever eat cottage cheese or yogurt? They're full of bacteria. In fact, if you get diarrhea you should eat cottage cheese afterwards to replace the beneficial gut bacteria that the diarrhea flushes out.

What assurances do we have that the bacteria in cottage cheese won't mutate, self-replicate, or turn against you in the form of some horrendous new super-bug that makes the 20,000 la

What assurances do we have that the bacteria won't mutate, self-replicate, or turn against its master in the form of some horrendous new super-bug that makes the 20,000 land-mine casualties a year seem li

Why is this parent modded 'funny' ? In Eastern and African countries little kids *are* actually being used to detect mines: by blowing them up, and losing their arms, legs, or lives... I do not see what's so funny about that at all...

why can't they do something similar and temporarily be celebate to avoid being responsible for all of that misery and suffering?

The social/cultural issues are for more complex then that. A vast majority of women in these countries can't because they don't have the rights to. The stats on rape in some countries are hideous, and many women are stuck in relationships where they can't tell their partner to use birth control and they can't get out of these relationships for any number of religious/socio-economic/cultural reasons. The guys in many of these countries still have this idiotic notion that using a condom isn't manly and theref

A friend of mine was in africa a while back and had noticed something peculure when he visited many years ago, the women always walked behind the men, now many years lator, the men walk behind of the women. When he asked one of the viligers if there was a feminist movement and if women were more more prominent, the viliger said No Land Mines!

I don't think this invention is being touted as a militarily useful tool. It's intended to help with the cleanup of the bazillions of mines that are still hidden in many many parts of the world where fighting has long since stopped, but the mines still remain behind.

If the US military needs a path through a suspected minefield, they're not going to spray this stuff, wait a few hours, then send some soldiers out to individually dig up all the green spots. They've got machines that are basically giant armored bulldozers that they can use to cut a straight path through. They also have trucks that basically fire a chain of explosives that clear out a straight path. But it's not feasible to use these techniques for large scale clean up because there's too much ground to cover, and it's a very destructive process.

So you're probably right that if someone was laying down a minefield this afternoon they could find some fairly easy ways to counter this bacteria. Fortunately, I don't think anyone is going to spend the time and expense to spray explosive residue around a bunch of mines that were buried in WW2

...but these bacteria glow green, which is a 2. I can't figure out how to make a minefield that only has 2's so this problem is more complicated than we thought. If only they made blue-glowing bacteria instead...

I really like us to come up with better debugging techniques before we go further into these bio-engineering stuff.

You may not think much about it but ways to safely detect landmines can save a number of arms, legs, and lifes. They could help avoid another child losing a leg while playing in a field where landmines were placed.